398732221 has 2 divisors, whose sum is σ = 398732222. Its totient is φ = 398732220.

The previous prime is 398732219. The next prime is 398732287. The reversal of 398732221 is 122237893.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 397005625 + 1726596 = 19925^2 + 1314^2 .

It is a cyclic number.

It is not a de Polignac number, because 398732221 - 2¹ = 398732219 is a prime.

Together with 398732219, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (398732821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199366110 + 199366111.

It is an arithmetic number, because the mean of its divisors is an integer number (199366111).

Almost surely, 2^398732221 is an apocalyptic number.

It is an amenable number.

398732221 is a deficient number, since it is larger than the sum of its proper divisors (1).

398732221 is an equidigital number, since it uses as much as digits as its factorization.

398732221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 36288, while the sum is 37.

The square root of 398732221 is about 19968.2803716294. The cubic root of 398732221 is about 736.0270529252.

The spelling of 398732221 in words is "three hundred ninety-eight million, seven hundred thirty-two thousand, two hundred twenty-one".